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Pro soldering techniques and guidelines for electronics PCB soldering


A solder is a kind of metal that is produced by melting iron at a high temperature. Soldering is a process that may be completed using a variety of methods and techniques. However, most professionals and industry experts choose to employ the approach in which two distinct kinds of metal pieces are united on the surface of the printed circuit board (PCB).

PCB soldering is a crucial process and plays an important role. In simple words, the term “PCB soldering” refers to the process of joining or connecting two or more distinct types of electronic devices. By using a melting operation to fuse the various metals together, the technique of PCB soldering is quite useful for establishing a robust connection and bond between the various types of metals.

What are the steps to PCB soldering?

When you are working on the PCB soldering procedure, it is very important to know what steps and procedures are included in it. This knowledge is even more important because it is quite critical. In the PCB soldering procedure, each individual step is important for its own reason.

1.In the beginning, you will need to mark the holes on the board. The metal’s sections and components should then be carefully positioned on the pointed holes that have been indicated.

2.To secure it in place, gently bend the leads, but do so with caution because the component could be damaged if the bending is done too violently.

3.During the PCB soldering process, it is extremely important to heat every part of the board at the same rate. In order to ensure that the lead of the part and the pad are heated to the same temperature, it is necessary to position the solder tip over the pad.

4.Because it is essential to apply solder to each individual part, the heating method is repeated until the solder melts and can then be applied to the component’s individual parts in the correct manner.

5.Now that the checking step in PCB soldering has arrived, remove the iron and the solder wire, and check to see if the solder joint was completed correctly.

6.The shape of a cone will be formed by a good solder junction. In the event that the shape is constructed correctly, the component lead can be severed.

What are the types of soldering?

★Hard (silver) soldering

★Soft soldering


The function of flux in PCB soldering

The cleaning of electronic components is an extremely important step in the process of soldering circuit boards (PCBs). As a result of this, flux is utilized. Flux is a well-known chemical, and the electronic components that require cleaning and purification are typically treated with flux. The process of soldering printed circuit boards (PCBs) involves the attachment of a large number of chemical and dust particles to the circuit boards, after which flux is used to clean the PCBs.

Not only is it favored in the process of soldering PCBs, but it is also utilized in hand soldering operations. The ideal soldering mechanisms for PCBs can be achieved with the help of flux. During the PCB soldering process, the flux prevents the metal surfaces from reoxidizing and assists in the process by modifying the surface pressure of the molten material. Additionally, the flux prevents the reoxidation of the metal.

The fundamental component of flux is a chemical activator that functions to remove dust and oxides from the surface of the metal in order to facilitate a more effective PCB soldering process.

The difference between brazing and the reflow soldering

☆Reflow Soldering
The method of reflow soldering involves creating a paste consisting of a sticky flux and minute particles of metal solder. During the heating up phase of the PCB soldering process, this paste has the ability to hold the components in their appropriate positions. The air is stopped from moving by the thick and sticky nature of the flux, which also removes further oxidation. This flux has a cleaning and purifying property, which cleans and purifies the outer surface of the PCB.

By melting and heating the filler metal, the technique of brazing can link together two or more separate components. When they need to combine the pieces of metal without melting the metal that the parts are comprised of, most professionals favour this technique as the best option. When there is a requirement to combine metals that have various properties, this process is frequently used because it is highly popular.

What is hard PCB soldering and soft PCB soldering?

 ☆ Hard PCB Soldering
When we discuss the hard PCB soldering technique, we are talking about the process in which two metals are fused by enlarging the distance between the spread-out components. Basically, two smaller processes are taken into consideration in the hard soldering procedure. These processes are frequently referred to as brazing soldering and silver soldering.

When liquid filler metals are used to connect the base metal end points, the brazing PCB soldering technique is adopted. This method is renowned for its strong metal end-to-end connectivity.

In contrast, the silver soldering technique is used to fill in the gaps between the various components on the circuit board. This method is very widely known for supporting various circuit board components. Silver is used for this operation, but experts advise against it as best practice. Flux is typically preferred by professionals and is regarded as the best practice for silver soldering.

 ☆ Soft PCB Soldering
A soft PCB soldering process is used if it is necessary to attach small metal elements to a large PCB. The fundamental idea underlying that mechanism is that certain of the metal’s more microscopic constituents have a lower condensation temperature than others. As a consequence, when these constituents are heated, they will separate from one another.

Filler metal is used in an advanced degree of procedure that is performed in order to improve the adhesion of metal pieces to the printed circuit board (PCB). Lead and tin are the two metals that go into making up the filler metals. Utilization of fillers takes place during the process of soft PCB soldering. The filler functions similarly to glue and gives the metal parts and the printed circuit board more strength.

Steps of reflow soldering in detai

In the first step of the reflow soldering process, which is called “preheating,” the circuit board is heated at a low but constant temperature. If the temperature were to be high, it would likely cause spots to appear on the surface of the board.

2.Soak up the heat
After going through the preheating process, the boards will reach the ideal temperature. After that, the board is transferred to the location where it will be thermally sacked. The most important thing to remember is to keep the temperature consistent and low all the time.

During this stage of the process, the temperature of the board reaches its maximum level. In this stage of the process, the procedure of joining molten solder and solder joint is carried out. Because the flux that is used in this operation lowers the surface tension at the joints, the technique of joining the metals is carried out at the greatest temperature possible. The major explanation for this is found in the previous sentence.

This is the final stage, and at this point, the boards need to be allowed to cool down. At this stage, though, one thing that you need to make sure you keep in mind is that the cooling action does not generate spots on the board.

Why soldering is so important in PCB design and manufacturing?

Soldering is an essential step in PCB design because it facilitates the connection of the numerous electrical components that are housed on the circuit board. As a result of this, the PCB manufacturing procedure incorporates a wide variety of different mechanisms in order to guarantee its success. The term “pick-and-place” refers to a well-known method of soldering that is utilized when it is necessary to lift pieces of metal and set them on a circuit board.

Soldering processes have been an important component in the creation of printed circuit boards (PCBs) because they guarantee that the PCBs will continue to function reliably for a very long period. This has made the soldering process an important component in the production of PCBs. Soldering is essential for maximizing the usefulness of printed circuits, which are now employed in every digital device. Soldering is the key to unlocking this functionality.

How to evaluate the quality of the PCB soldering?

●Dip and look
Dip and look For testing solderability, steam is used for 0–8 hours. Activated rosin flux is used to clean the parts, and then they are dipped in solder. Pieces are checked for quality after being dipped.

●The simulation test for surface mount
For surface mount simulation testing, a certain solder paste is screen-printed onto a ceramic plate, and a convection reflow profile is used. Surface mount simulation testing can be used on both BGA and CGA components that are mounted on the surface.

Tips for PCB soldering

◆Using the correct tools
You should never forget to pick up the appropriate tools, as successful work can only come from using proper tools. In addition to this, you need to be familiar with how to operate the appropriate instrument.

◆Lead-free solder
To avoid a harmful atmosphere, lead-free solder is preferred. Lead-free solder retains tin but replaces lead with copper and silver. Leaded solder melts at 220°C. Lead can be ingested, inhaled, or absorbed via the skin. Use a fan to air your workspace and wash your hands after handling lead-based solder.

◆Use of heat sinks for a quick soldering tool
Soldering heat can harm some parts, so if you’re new to it, utilize a heat sink. Heat sinks prevent reed switches, transistors, and integrated circuits from overheating (ICs).

◆Using plumbing solder carefully for electronics
Solders for electronics may have a flux core. Flux improves solder flow but consumes metal. Flux cleans chemicals. The solder cleans as it melts. On clean, non-oxidized metal, solder flows easily. Use fine-grained sandpaper to remove oxidation before soldering.

This strengthens soldered connections. Oxidized coatings can block solder from reaching leads or wires. This makes the coating an insulator by stopping electron movement. Solder isn’t just for electronics. Plumbers use it to “sweat” pipes and fittings together, while stained glass utilizes it between soldered glass pieces. You shouldn’t use plumbing solder in electronics.

◆Use of a soldering iron stands
Whether you’re soldering pipes, stained glass, or electronics, use a soldering iron stand. Soldering irons can create serious burns, flames, and poisonous gases from flammable materials.


PCB soldering is a simple way to solder that anyone who is interested in the field of electrical machines can use. If you can learn this important skill and put it to good use, you will save time and money in the long run.

I really hope that by now you have a good understanding of how soldering works. If you follow this plan, you will be able to solder the parts onto a new PCB board. If you want to replace a PCB component, you will first have to desolder the component that needs to be taken off the PCB. After that, you’ll be able to change out the part. You can use a heat gun, a desoldering pump, or something else to get the solder off the part, but you don’t have to. After removing the part, you can follow the steps above to install the new part in its place.




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